At the 3rd international conference on Trust and Trustworthy Computing (TRUST 2010), workshop on Anonymous Signatures,
Berlin, Germany, June 2010.

Invited presentation.

Abstract

In this talk, I will describe a useful cryptographic tool for expressive anonymous signatures. The tool allows one or several signers to create digital signatures with a very finely tunable level of anonymity: it gives them the ability to conceal their identities, within a larger group, to a very precise extent. I will discuss two variants of the same general approach: one that provides unconditional anonymity in arbitrary groups (useful in adversarial contexts such as whistle-blowing), and another that provisions a traceability mechanism within an authoritative group (useful in accountable collaborative settings such as corporate and government).